Facebook announced Monday that it has bought TBH, an anonymous polling app popular among teens. The acquisition emphasizes Facebook's method of buying or copying rival services and its push to attract younger users.

TBH, which stands for "To Be Honest," launched less than three months ago and already has more than five million downloads. The app describes itself as giving anonymous feedback to friends that is strictly positive. It does this by asking users to pair an emoji with a prompt about one of their friends who, for example, "wouldn't mind snuggling up with them during a movie."

The app was created in August by co-founders Nikita Bier, Erik Hazzard, Kyle Zaragoza, and Nicolas Ducdodon. Bier originally launched TBH's parent company Midnight Labs in 2010 with the hopes of becoming an app studio, but the products never took off. Midnight Labs was losing money, and with just 60 days of cash left, the creators decided to build something similar to popular and anonymous apps like Yik Yak and Secret--but with a positive spin.

"We think the next milestone is thinking about social platforms in terms of love and positivity," Bier told TechCrunch in September. "We think that's what's been missing from social products since the inception of the internet."

TBH first launched in Georgia and has quickly expanded to 37 states. While it's not yet profitable, there are no current plans to monetize the app, according to TBH's website. The app soared in ranking in the iOS App Store, making it an attractive acquisition for Facebook.

TBH will run as a standalone app under Facebook, and the co-creators will become Facebook employees so they can oversee TBH's expansion. A Facebook spokeswoman declined to tell The Wall Street Journalthe price of the acquisition.